Being ambulatory, such as running and walking, is a universal and timeless mode of exercise and sport. Training regimes for improving ambulatory movement are many, but most involve simply more of either running or walking, often with some sort of structured workout such as repeated cycles of distance and/or pace, timed distances, hill training, and other measured, controlled workouts.
Some runners and walkers augment such ambulatory workouts with weight-lifting or static resistance training using a resistance-providing machine. For example, some runner and walkers workout on weight benches to build muscle, particularly leg muscle. The resistance provided by such machines increases the normal gravitational resistance experienced by a person.
However, using enhanced resistance while moving in a natural ambulatory setting has proven difficult. Some runners and walkers have used weights that are placed at their ankles or on their wrists. But such weights alter the person's natural gait and tempo, which is difficult to adjust to when the weights are not used.